Known in the art is an intermittent epicyclic mill (SU, A, 117,671) incorporating a housing with a cover, barrels with lids and loads of pebbles which are linked to planet wheels of a planetary gear, and a drive, whereby each barrel is fitted to a mount--which is fixed to a planet wheel--and is provided with an overhanging clamp comprising an eccentric and a pushrod interacting with the barrel lid. The pushrod can consist of two lengths connected by a spring.
The barrel lids are opened and closed by the hand-operated eccentrics, and the opening and closing of the housing cover is a manual job as well. Therefore, the attending personnel is exposed to the harmful effect of the toxic stock processed and may suffer from poisoning and occupational diseases, putting them on the sick list.
Also known is an intermittent epicyclic mill (SU, A, 961,760) incorporating a baseplate-supported housing with a cover contained wherein are barrels revolving about their own axes and the axis of the mill. The barrels rest on a carrier, are provided with lids and contain each a load of pebbles. The carrier is electrically driven.
The fasteners of the barrel lids and housing cover are done and undone by hand. Therefore, when toxic stock containing, e.g., mercury, fluorine, barium, etc. being processed, the personnel is exposed to its hazardous effect with grave consequences for their health.